OFFSET
1,1
COMMENTS
The next term after 347 is bigger than 2250. - Stefan Steinerberger, May 05 2007
No other terms less than 100000. - Robert Price, Mar 18 2012
LINKS
H. Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927-930.
H. Lifchitz, Mersenne and Fermat primes field
Index to primes in various ranges, form ((k+1)^n-1)/k
MATHEMATICA
Select[Prime[Range[100]], PrimeQ[(26^#-1)/25]&]
PROG
(PARI) is(n)=ispseudoprime((26^n-1)/25) \\ Charles R Greathouse IV, Feb 17 2017
CROSSREFS
KEYWORD
hard,more,nonn
AUTHOR
Alexander Adamchuk, Feb 11 2007
EXTENSIONS
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008
STATUS
approved